This is a protocol for a Cochrane Review (prototype). The objectives are as follows: To assess the effects of weight-neutral interventions for managing obesity in children and adults (quantitative data). To explore the views, perspectives and experiences of children and adults receiving the intervention, their close family members or, if appropriate, carers, and healthcare personnel who recommend or deliver weight-neutral interventions to determine their feasibility and acceptability and any factors that create barriers and facilitators to optimal implementation (qualitative data). To determine whether the programme theories, components and delivery of interventions take account of the views, perspectives and experiences of intervention recipients and whether patient-centred interventions have greater effects.